---
title: List
description: Adapter that performs whitelist or blacklist checks.
location: https://istio.io/docs/reference/config/policy-and-telemetry/adapters/list.html
layout: protoc-gen-docs
generator: protoc-gen-docs
supported_templates: listentry
aliases:
  - /docs/reference/config/adapters/list.html
number_of_entries: 2
---
<p>The <code>list</code> adapter makes it possible to perform simple whitelist or blacklist
checks. You can configure the adapter with the list to check, or you can point
it to a URL from where the list should be fetched. Lists can be simple strings,
IP addresses, or regex patterns.</p>

<p>This adapter supports the <a href="https://istio.io/docs/reference/config/policy-and-telemetry/templates/listentry/">listentry template</a>.</p>

<h2 id="Params">Params</h2>
<section>
<p>Configuration format for the <code>list</code> adapter.</p>

<table class="message-fields">
<thead>
<tr>
<th>Field</th>
<th>Type</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Params-provider_url">
<td><code>providerUrl</code></td>
<td><code>string</code></td>
<td>
<p>Where to find the list to check against. This may be omitted for a completely local list.</p>

</td>
</tr>
<tr id="Params-refresh_interval">
<td><code>refreshInterval</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Determines how often the provider is polled for
an updated list</p>

</td>
</tr>
<tr id="Params-ttl">
<td><code>ttl</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Indicates how long to keep a list before discarding it.
Typically, the TTL value should be set to noticeably longer (&gt; 2x) than the
refresh interval to ensure continued operation in the face of transient
server outages.</p>

</td>
</tr>
<tr id="Params-caching_interval">
<td><code>cachingInterval</code></td>
<td><code><a href="https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#duration">google.protobuf.Duration</a></code></td>
<td>
<p>Indicates the amount of time a caller of this adapter can cache an answer
before it should ask the adapter again.</p>

</td>
</tr>
<tr id="Params-caching_use_count">
<td><code>cachingUseCount</code></td>
<td><code>int32</code></td>
<td>
<p>Indicates the number of times a caller of this adapter can use a cached answer
before it should ask the adapter again.</p>

</td>
</tr>
<tr id="Params-overrides">
<td><code>overrides</code></td>
<td><code>string[]</code></td>
<td>
<p>List entries that are consulted first, before the list from the server</p>

</td>
</tr>
<tr id="Params-entry_type">
<td><code>entryType</code></td>
<td><code><a href="#Params-ListEntryType">Params.ListEntryType</a></code></td>
<td>
<p>Determines the kind of list entry and overrides.</p>

</td>
</tr>
<tr id="Params-blacklist">
<td><code>blacklist</code></td>
<td><code>bool</code></td>
<td>
<p>Whether the list operates as a blacklist or a whitelist.</p>

</td>
</tr>
</tbody>
</table>
</section>
<h2 id="Params-ListEntryType">Params.ListEntryType</h2>
<section>
<p>Determines the type of list that the adapter is consulting.</p>

<table class="enum-values">
<thead>
<tr>
<th>Name</th>
<th>Description</th>
</tr>
</thead>
<tbody>
<tr id="Params-ListEntryType-STRINGS">
<td><code>STRINGS</code></td>
<td>
<p>List entries are treated as plain strings.</p>

</td>
</tr>
<tr id="Params-ListEntryType-CASE_INSENSITIVE_STRINGS">
<td><code>CASE_INSENSITIVE_STRINGS</code></td>
<td>
<p>List entries are treated as case-insensitive strings.</p>

</td>
</tr>
<tr id="Params-ListEntryType-IP_ADDRESSES">
<td><code>IP_ADDRESSES</code></td>
<td>
<p>List entries are treated as IP addresses and ranges.</p>

</td>
</tr>
<tr id="Params-ListEntryType-REGEX">
<td><code>REGEX</code></td>
<td>
<p>List entries are treated as re2 regexp. See <a href="https://github.com/google/re2/wiki/Syntax">here</a> for the supported syntax.</p>

</td>
</tr>
</tbody>
</table>
</section>
